Safety check valve



May 8, 1928.

H. M MlLLAN SAFETY CHECK VALVE Filed Dec. 14. 1920 Patented May 8, 1 928.

HARRY M M AN I eDELRal PENNSYLVANIA- SAFETY annex VALVE.

Application filed December 14, Serial No. g3o,791

My invention relates more particularly to safety check valves for use wheresexploslve mixtures of gas are used in internalconr bu'stion engines,-gas ranges, furnaces and the like, and has for its object the'prevention of what is known as back-fire in such apparatus.

Another object of my invention is to so construct the valve that there shall be the least resistaneeto the flow of the gases through the valve. lVith these ends in View, this invention consists in the details of construction and combination of elements hereinafter set forth, and then specifically designated by the claims; i I

In order that those skilled in the art to which this invention appertainsmay understand how' to make and use the same, I will describe its construction in detail, referring by numerals to the accom ianying drawing forming a part of this specification, in which, i V

Figure 1 is a plan "lGW'OfflllQ check valve made in accordance with my improvement, broken away to illustrate the-internal construet-ion thereof. w Figure 2 is a section of the same on the line 22 of Figurel,

Figure 3 is a i ragmental end; view "of the bodied, 1 represents thelower member of the check valve and 2 the upper member; the inlet 3 and a gasket 6 is inserted to make the joint gas proof. The lower member 1 has a recess 7 in which is placed a double wire gauze 8 and 9, separated or spaced by a ring 10 to which the gauze can be soldered. the ring being fitted tightly in the recess. Above this recess is the seat which can be made as shown with a flat portion 11, a raised portion 12, and another flat portion'13, or this seat can he waved with two or more depressions, 14

being a ring of leather or other suitable ma terial which may be cemented to this seat. The disk 15 is made as light as possible, has convolutions conforming with the seat and. can be dished in the center to give greater strength. It is held down by the slight pres sure of the spring 16. as shown, which also tends to center it. Gauzes 17 and 18 are attached to a ring 19 and fitted into the recess 20 of the upper member 2. The mem- In carrying out my invention, as here emis threaded as is theoutlet' 4, the two members are held together by the screws 5,

her 2, is provided with a blow out plate 21 of the sameorsimilar material as the valve cas ng men'ibers and which has only the opening 23 leading to the 'ehan' ber 24 above the gauze 18 but this opening considerably greater area than the outlet 1. The pocket 25 may vary in shape but the opening 23 must be below the bottom wall or the outlet 1.

' It is evident that the inlet and outlet can be in a more or less vertical plane it de sired. I

Theuse of an explosive vapor, that is, a

Dillgtllltif gas and air in well known proportions, is not considered satein driving internal combustion engines for the reason that there is a chance (it a lean mixture of gas igniting, notexploding, in'the cylinder; this fire may remain andwhon the admission valve is again opened, it may ignite the incoming gas and cause it to back-fire; Now, it there any considerable volun' e of such explosive gas that the hack-tire can reach, the result'cnayibe a serious explosion and tlicyhave been known to occur.

lVhenmy improvement isnsecl the check yalve' disk 15 isalways seated, unless there which there is (not if cylinder the check and the engine can be" ignited; there is however'stillthe remote chance that this firemay not be lout before the e S eks n w 1 a through the check and the fire ii ight follow theiincomiin gash cl: to the tank indexplode it.""I have therefore inserted screens made. of copper or brass wire mesh in the s is burning in the passages leading to and from the check, and

have designed these so that they have a relatively abnormal area in comparison with the area of the feed and discharge pipes so that the flow of the gas shall be very slow through the screens.

It has been recognized for the past hundred years that such a screen or gauze will not allow a flame to pass itunless the speed of gas exceeds six feet per second, this being due to the coolingelfcct of the large surface of metal in proportion to the size of the holes left in such a gauze, and this effect does not seem to be changed if the temperature of the gas is raised to over 120 deg. F. It is alsorecognized that two or more such screens, if'clean, are many times more effective than a single screen. By properly prolevel of the considerablesuction hem the engine,

- m 4- r v and therefore only the gas between 7 v next suc- This will draw gas is made of portioning the screen area to the flow of gas I can insure the prevention ot any flame passing.

As the above description stands the valve might not yet be safe against a distinct explosion of gas in the outlet. I have therefore provided the pocket into which the first effect of an explosion, as a rapidly moving body of flame is understood, will be pro jected, because it has been demonstrated that such a movement is projectile and tends to follow a straight line, but, if pocketed, will at, once knock itselt'out. I

The screens have another important function, for as the gas and air pass them they are sieved and the mixture made much more intimate than if the sameproportions oi gas and air are simply drawn through a tube where the slight friction of the walls is the only disturbing "factor to the straight flow; and the better the air and gas vapor are mixed the more effective their joint explosion is in performing work in the cylinder. .7

Of course I do not wish to be limited to the exact details of construction here shown, as these may be varied within the scope of the appended claims without departing from the spirit of my invention.

Having thus fully described my invention which I claim as new and useful is 1. A safety check valve including a casing having an inlet, an outlet and a seat between said inlet and outlet, a valve disc coacting with saidseat, and an apertured blow-out plate located between the outlet and the valve seat and forming with the walls o1 the casing a pocket in alignment with the outlet.

2. A safety check valve including a casing having an inlet, an outlet and a seat between said inlet and outlet, a valve disc eoacting with said seat, and a blow-out plate located between the outlet and the valve seat and forn'iing a pocket between it and the walls of the casing, said pocket being in alignment with the outlet and said plate having an aperture therein ad acent the outlet.

'3. A safety check valve including a caslocated between the outlet and the valve seat with the portion of said plate adjacent the outlet lying in a plane below said. outlet, said portion having an aperture therein of greater area than said outlet, said blow-out plate forming with the walls of the casing a pocket beyond the aperture in alignn'ient with the outlet.

a. A check valve comprising a casing having a passageway theretln'ough, a valve disc within the passageway for normally closing said passageway and a pocket in said passa eway on one side of the valve disc.

5. A check valve comprising a casing having an inlet and an outlet, a valve seat within the casing and between the inlet and the outlet, a member to coact with the valve seat, and a pocket'within the casing on one side of the valve seat.

6. A check valve comprising a casing having a passageway therethrough, a valve member within the passageway for normally closing the passageway, a spring to actuate the valve member to normally close the passageway and a pocket in said passageway on one side of the valve member.

7 A check valve comprising a casing having an inlet and an outlet, a passageway connecting the inlet and outlet, a valve seat within the passageway and a pocket in the passageway between the valve seat and the outlet.

8. A check valve comprising a. casing having an inlet and an outlet, a passagewav connectingthe inlet and the outlet, a valve between the inlet and the outlet, and a pocket formed in line with and at the inner end of the bore of the outlet.

HARRY MACMILLAN. 

